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Lies, damned lies and health statistics
By Niall Hunter-Editor
Are you sometimes confused by the plethora of health information that is bombarded at you nowadays, some of which may be contradictory?
The information revolution of recent decades has had many advantages for the health consumer in terms of being generally better informed, but the downside is that many people become confused by information overload, a common question being- ‘is X food/medicine/treatment etc beneficial or not?”
Well, don't worry, you're not alone, nor is your condition unusual. A new report from Ireland has stressed that this is a common complaint nowadays, and the cause is the intrinsic complexity of human health coupled with the sometimes distorted way health issues are presented, reported and discussed.
This criticism, of course, could not possibly apply to irishhealth.com! However, the report, from the Society of Actuaries in Ireland (SAI), makes for interesting reading.
It points out that health issues are fundamentally complicated because human biology is complicated.
The health effects of various medical treatments, foods, environmental conditions etc, are also complex and will vary from one person to another, depending on their circumstances and genetic make-up.
The report points out that something that has a positive health effect in one way may have a bad effect in another.
One example would be that drinking high levels of alcohol is clearly damaging, while consuming moderate levels may actually benefit health. The crossover point, however, that is, when it stops doing you good and starts harming you, is difficult to determine and may be different for each individual.
The SAI says it is generally difficult and often impossible to get conclusive results on human health issues for a number of reasons including-
*Scientists usually study cause and effect by experimentation, but there are obvious ethical restrictions in experimenting on humans;
*The assessment of long-term benefits or risks (for example of taking a drug) requires observations of large numbers of people over long periods of time;
*It is practically impossible to allow for all the other potential variables when one particular factor is being studied in, for example, in a clinical trial;
*Most studies can only identify an association, not cause and effect, between a particular factor and particular health benefits or risks;
*One risk factor can be related to another factor and it may not be possible to isolate the impact of one particular factor.
The report says the way in which information is presented, reported and discussed can also distort the picture. Health scares, according to the SAI, are more likely to receive attention rather than 'good news' stories, and there is an equal risk that positive health stories can be 'oversold'.
While the results of medical research may include a number of 'caveats' and qualifications in the original research paper, often the results can be presented in the media in a much too positive light.
The report also points out that health statistics can often be misleading-
*The importance of a percentage increase or decrease in the incidence of an illness depends on how common the illness is to begin with. A small change to the incidence of a common illness is likely to be much more significant than a big change to how often a rare illness occurs. For example in Ireland, a 5% drop in heart disease would have a significant impact on the overall death rate for the illness, whereas a 50% increase in the incidence of vCJD would have a negligible impact on overall mortality, given the smaller numbers involved. So a media report may say that the incidence of a disease has doubled, when it may have only increased form 1% to 2%.
*Where the number of people with a particular illness is quoted it may create a perception that the risk of suffering the illness is greater than is actually the case. For example, as well as saying that 10,000 Irish people have a particular disease it would, according to the SAI report, be helpful to explain that this means that 0.25% of the population suffers from it, or that the odds of getting the disease are 400 to one.
The report also points out that reporting the number of deaths from a particular disease should take account of the fact that everyone is going to die of something eventually and particularly for the very old, multiple causes may be implicated, although death may be attributed to one particular cause, so the number of deaths from a particular disease may provide a misleading picture as to the overall impact of that disease.
The report says it is therefore useful to make comparisons in terms of the number of 'years of life lost', as well as the number of deaths. For example, the number of years of life lost in Ireland due to accidents and suicides is greater than the years lost thorough all cancer deaths.
The SAI also stresses that some research may be produced by parties with vested interests or a particular agenda;eg promoting a particular product, and the media should point this out.
The report also points out that results based on a small study group are not always a reliable indicator of the outcomes for the population as a whole, and larger studies are usually more reliable.
It also stresses that comparisons of health statistics between different countries can be fraught with statistical pitfalls, as factors such as healthcare practices in different states have to be taken into account.
The report stresses that important information on health matters may not always get the attention it deserves, while in some cases the potential consequences of misinformation can be serious.
People, it says, need to take care as to how they act on information that may be misleading. Headlines, or simplistic statements should not always be taken at face value and detailed evidence in support of particular claims on treatments or lifestyle changes should be sought.
It is also important, says the SAI, to ensure that information is from an unbiased and reliable source.
Most important of all ,when in doubt, always consult a medical professional.
The report concludes on a positive note. Despite all the headlines about health risks, our overall state of health is better now than at any time in the past. So, some unbiased good news at last!
|Alistair(YIG32089) Posted: 27/07/2005 23:13|
|Very important article. I hope that it will be widely read and understood. The media should always explain from where they got the article on a health matter.|
|Anonymous Posted: 28/07/2005 11:02|
|This is very true. Sometimes information in the media seems confusing and even contradictory as time goes on.|
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